PROJECT SUMMARY/ ABSTRACT DESCRIPTION: See instructions. State the application's broad, long-term objectives and specific aims, making reference to the health relatedness of the project (i.e., relevance to the mission of the agency). Describe concisely the research design and methods for achieving these goals. Describe the rationale and techniques you will use to pursue these goals. In addition, in two or three sentences, describe in plain, lay language the relevance of this research to public health. If the application is funded, this description, as is, will become public information. Therefore, do not include proprietary/confidential information. DO NOT EXCEED THE SPACE PROVIDED. Autism Spectrum Disorder (ASD) is a common, often devastating neuropsychiatric condition with largely unknown pathophysiology. Although ASD has a multifactorial etiology, it encompasses a large genetic component. The investigators in this proposal aim to continue and enhance our collaborative effort that has produced significant advances in our understanding of ASD over the last four years and generated highly successful, open data and biomaterials resources for the research community, the NIMH Genetics Initiative and the Autism Genetic Resource Exchange (AGRE). Our Network has met or exceeded our original aims. We have built patient resources for research, identified rare and common ASD susceptibility alleles, defined models of ASD genetic susceptibility, provided evidence for convergent pathophysiology, and led development of animal and cell culture models. Here we propose to take a major new direction, filling a significant gap in ASD research, by recruiting underserved subjects of self-reported African ancestry (African-American; AA), an important population that has not previously been well-represented in ASD genetics research. Our Network involves six research sites and the AGRE DCC, collaborating in a systematic, comprehensive investigation of ASD genetics in order to identify rare mutations, chromosomal abnormalities, and common variation contributing to ASD susceptibility in the AA population. Specifically, we will enrich existing resources by recruiting at least 600 AA probands and additional family members. Our recruitment plan includes an embedded health disparities project that will evaluate access to care for AAs with ASD and clarify factors influencing participation of AA individuals in genetic research. We will employ novel methods to define the ancestral origin of specific chromosomal segments and ascertain the background on which susceptibility alleles occur. We will perform follow up GWA on ASD-related endophenotypes or co-variates, such as language delay, sex and head circumference. In parallel, we will conduct whole exome sequencing (WES) and analysis of copy number variation (CNV) using 2.5M SNP arrays yielding high resolution molecular karyotypes and providing a resource on genome-wide CNV and coding sequence variation (SNV) in ASD. Gene expression profiling and network analysis will be used to prioritize variants. Genetic risk factors identified in the mostly European samples will be tested for association in the AA sample to determine whether these cohorts share the same genetic risk factors, using a sample size providing power to replicate previous associations and to identify rare, recurrent CNV and SNV. The observation of new forms or different population frequencies of ASD-related variation in this sample as well as the sharing of most CNV and SNV with other cohorts are both outcomes that will have great significance for future studies and clinical care. As has been our practice, our Network will make all phenotypic and genotype data accessible via the internet on a rolling basis, further enhancing the value of this resource to the community.